this paper, Pishan county sewage treatment and the desert greening have been studied. We have analyzed the advantages and disadvantages of the wetland mechanism and its purification in the sewage treatment in Pishan county as the test results of reused sewage for greening the desert. It has proved that the constructed wetland sewage can be made to receive significant environmental, economic and social benefits. Deeply studying has demonstrated that constructed wetland mechanism in arid areas will change the environment of Xinjiang and that of the country.